I'll rummage through my docs to check, but I think that the Inside Macintosh series may be the source of some misinformation. ISTR that the Hardware Reference leaves the impression that there is only one power supply that works for all, save for the jumper. But my memory was never any good, and it hasn't gotten any better with age, so I will have to double check this to be certain.

Slomacuser -- I recommend not experimenting with high mains voltages until this gets cleared up. You run the risk of liberating much magic smoke.